Some vehicle lamps, such as vehicle headlamps, have a structure that allows an irradiating direction to be changed while the vehicle is operating.
For example, in some vehicle lamps, an irradiating direction can be adjusted in right-and-left directions while the vehicle is operating (see, e.g., JP 2004-227933 A). Thus, when turning right or left, or when traveling along a winding road, light can be forwardly irradiated in advance in the direction the vehicle is to be turned, thereby enhancing traveling safety.
A lamp unit of the vehicle lamp can be formed with a shaft, which swivelably supports the lamp unit on a support member, and a joint portion, which couples the lamp unit to a driving device operable to swivel the lamp unit. In other words, the lamp unit needs to be specially designed so that it can be swivelably supported on the support member and coupled to the driving device. Therefore, a lamp unit for a vehicle lamp which does not have a function of changing an irradiating direction while the vehicle is traveling cannot be used in a vehicle lamp which has the function of changing an irradiating direction while the vehicle is traveling. Likewise, a lamp unit for the vehicle lamp which has the function of changing an irradiating direction while the vehicle is traveling cannot be used in a vehicle lamp which does not have the function of changing an irradiating direction while the vehicle is traveling. Thus, dedicated lamp units have been required for the respective types of vehicle lamps.